This invention relates generally to the field of wheelchairs and more specifically to a motorized wheelchair machine with stand-up capability.
The field is crowded and comprises many variations on the common theme, that of wheelchairs with stand-up support capability. A number of representative designs are discussed in the following paragraphs.
U.S. Pat. No. 4,119,164 (Fogg. Jr., et al) teaches a long wheel base motorized wheelchair with stand-up capability. The design suffers from lack of maneuverability due to the fact that its drive wheels extend out in front of the chassis beyond the toes of the user. Because the drive axle is not physically beneath the user's feet, but is in front of them, it requires turning space of twice its own length to pivot around. This also makes it poorly adapted for fitting into space on public transport or private vehicles.
U.S. Pat. No. 5,096,008 (Manowski) teaches a three wheeled, motorized wheel chair. The drive wheels and entire drive system for the chair are located in front of the seated user. The design suffers from maneuverability disadvantages due to the long wheel base and is also, due to this length, poorly compatible with public and private transport.
Additionally, the armrests, as taught, extend in front of the unit, both in standing and in sitting position. In this, they comprise a potential obstruction to performing day to day tasks such as operating equipment and vehicles.
U.S. Pat. No. 5,137,102 (Houston, et al) teaches a motorized wheel chair with stand-up capability. The drive wheels and entire drive system for the chair are located in front of the user's toes and shins. The design suffers from a lack of maneuverability due to this feature in that the vertical axis about which it may pivot lies in front of the user. As a result it requires a space of at least twice its own length to pivot around this axis. Such maneuvering limitation is a disadvantage particularly in compatibility with public and private transport.
U.S. Pat. No. 5,366,036 (Perry) describes a motorized wheel chair having a drive axis behind the user's feet. As a result of this drive wheel location, the pivot turning axis lies behind the user, so that when the user undertakes to turn around, he actually swings in a circle, facing outward outside this axis of rotation. Additionally, the armrest mounted control station cannot be folded down, out of the way. It extends only forward or to the side, thus remaining a potential obstruction.
U.S. Pat. No. 6,125,957 (Kauffmann) teaches a motorized wheelchair with stand-up capability, wherein the drive wheels are located behind the user (i.e., the two rear wheels). As a result of the drive wheel location, the pivot turning axis lies behind the user, such that when the user undertakes to turn around, he actually swings around a circle outside his axis of rotation. So configured, this presents a maneuvering disadvantage in that the space required to pivot around is twice the physical length of the device. Additionally, the armrests extend rigidly forward, presenting potential obstacles to approaching equipment to be operated or other task locations.
U.S. Pat. No. 6,053,519 (Poindexter, et al) describes a motorized wheel chair with stand-up capability. It is configured with the drive wheels in front of the user, and also has a tower structure in front of the user, upon which the control console is located. So configured, this design presents significant obstacles interfering with the user's access to the area in front of him/her. For the user to approach a wash basin, window, or wall mounted control panel, for example, is very difficult, if not impossible. Also because the drive wheels are located in front of the user, when the user undertakes to turn around, he/she actually swings around a circle outside the axis of rotation. This tends to result in the user coming to rest at excessive distance from the target toward which he/she is turning.
U.S. Pat. No. 6,231,067 B1 (Johnson, et al.) describes a motorized wheel chair with stand-up capability. The seat pivots upward on an off-set hinge-like shaft arrangement at its front edge. The chair is equipped with armrests that extent forward or fold upward. No provision is made to have accessible means of chair control in all positions.